Ambient temprature removal rate constants for singlet methylene with some nitrogen and sulphur compounds

Abstract

<jats:title>Abstract</jats:title><jats:p>The technique of laser flash photolysis/laser absorption has been used to obtain absolute removal rate constants for singlet methylene, <jats:sup>1</jats:sup>CH<jats:sub>2</jats:sub> (ā A<jats:sub>1</jats:sub>), with some nitrogen and sulphur compounds at ambient temperature (298±2 K). A measurement of the removal rate constant for <jats:sup>1</jats:sup>CH<jats:sub>2</jats:sub> with NH<jats:sub>3</jats:sub> yielded a value of (3.33±0.19)xl0<jats:sup>−10</jats:sup> cm<jats:sup>3</jats:sup> molecule<jats:sup>−1</jats:sup> s<jats:sup>−1</jats:sup> in good agreement with the only previously reported measurement. Removal rate constants for the reactants CH<jats:sub>3</jats:sub>NO<jats:sub>2</jats:sub>, CH<jats:sub>3</jats:sub>CH<jats:sub>2</jats:sub>NO<jats:sub>2</jats:sub>, CH<jats:sub>3</jats:sub>CH<jats:sub>2</jats:sub>CH<jats:sub>2</jats:sub>NO<jats:sub>2</jats:sub>, CH<jats:sub>3</jats:sub>CN, CH<jats:sub>3</jats:sub>CH<jats:sub>2</jats:sub>CH<jats:sub>2</jats:sub>CN, CH<jats:sub>2</jats:sub>=CHCN, H<jats:sub>2</jats:sub>S, CH<jats:sub>3</jats:sub>CH<jats:sub>2</jats:sub>SH, CH<jats:sub>3</jats:sub>SCH<jats:sub>3</jats:sub>, CH<jats:sub>3</jats:sub>SSCH<jats:sub>3</jats:sub>, and CH<jats:sub>3</jats:sub>COSH were measured for the first time and found to be (3.23±0.28), (3.46±0.69), (3.55±1.28), (4.51±0.21), (3.64±0.41), (4.10±0.26), (3.87±0.22), (4.77±0.25), (4.53±0.23), (5.37±0.53), and (4.59±0.32)x10<jats:sup>−10</jats:sup> cm<jats:sup>3</jats:sup> molecule<jats:sup>−1</jats:sup> s<jats:sup>−1</jats:sup> respectively. The calculated removal efficiencies (removal rate constant relative to the Lennard‐Jones collision rate constant) are indicative of reaction being the dominant process leading to loss of <jats:sup>1</jats:sup>CH<jats:sub>2</jats:sub>. Comparisons are drawn between the reactivities of the nitrogen and sulphur functional groups and their hydrocarbon analogues, and between the sulphur compounds and their isoelectronic oxygen analogues.</jats:p>